JP2001323493A - Offset device of working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a working machine to perform an offset function with a simple structure and move a bucket in any direction. SOLUTION: This offset device comprises a first offset cylinder 29 installed between the lower boom section 21a and an upper boom section 21b of the working machine 20 and a second offset cylinder 30 installed between the upper boom section 21b and a cylinder stay 24. The first and second offset cylinders 29 and 30 are interfaced in a same manner. The first offset cylinder 29 is a master cylinder, and the second offset cylinder 30 is a slave cylinder. In the first operating mode for operating the two cylinders interlockingly with each other, a pressurized oil is fed from a hydraulic pump to the cylinders, and the directly operating cylinder is the master cylinder and the slave cylinder is operated by the introduction of the return oil from the master cylinder. The operating directions of these cylinders are reverse to each other and the strokes thereof are generally the same. In the second operating mode, the slave cylinder is operated independently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset device for a working machine of a hydraulic shovel for offsetting an arm with respect to a boom.

[0002]

2. Description of the Related Art A hydraulic excavator is provided with a working machine for performing operations such as excavation of earth and sand. For example, a hydraulic excavator having a configuration shown in FIG. 4 is widely used. In the drawing, reference numeral 1 denotes a lower traveling body having a crawler belt, and an upper revolving superstructure 2 is installed on the lower traveling body 1 so as to be capable of turning. The upper swing body 2 is provided with a working machine 3 for performing operations such as excavation of earth and sand. The work machine 3 is connected to the upper swing body 2 by a boom cylinder 4 so as to be capable of raising and lowering.
And an arm 7 rotatably connected in the vertical direction at the tip of the boom 5 by an arm cylinder 6, and linked to the arm 7 via a link mechanism 8 and rotatable with respect to the tip of the arm 7 by a bucket cylinder 9. And a bucket 10 as a front attachment.

[0003] The boom 5 has a lower boom 5a connected to the upper revolving unit 2 and a lower end having a lower end connected to the lower boom 5a.
And an upper boom 5b having a distal end connected to the arm 7. The upper boom 5b and the arm 7 are not directly connected, and the upper boom 5
The distal end of b is connected to the cylinder stay 11, and the base end of the arm 7 is also connected to the cylinder stay 11. Accordingly, the arm 7 is connected to the cylinder stay 11 so as to be rotatable up and down. On the other hand, the lower boom 5a and the upper boom 5b and the upper boom 5b and the cylinder stay 11 are rotatably connected. However, the rotation axes of both ends of the upper boom 5b are orthogonal to the rotation axis of the arm 7. That is, when the rotation axis of the arm 7 with respect to the cylinder stay 11 is set in the horizontal direction, the upper boom 5
The rotation axes at both ends in b are vertical directions.

Further, a lower boom 5a and an upper boom 5
b, an offset cylinder 12 is provided. By operating the offset cylinder 12, the upper boom 5b rotates in the horizontal direction with respect to the lower boom 5a. Reference numeral 13 denotes an offset stay. The offset stay 13 has a rod shape, and both ends thereof are pivotally supported by the lower boom 5a and the cylinder stay 11. Thereby, as shown in FIG. 5, a parallelogram link is constituted by the shaft supports 14, 15 of the upper boom 5b to the lower boom 5a and the cylinder stay 11, and the pivot supports 16, 17 at both ends of the offset stay 13. . As a result, when the offset cylinder 12 is extended or contracted, the arm 7 and the cylinder stay 11 connected to the arm 7 move in parallel to the left and right, and the arm 7 and the bucket 10 connected to the tip of the arm 7 , So as to be always parallel to the lower boom 5a. Therefore, when the offset cylinder 12 is actuated, the bucket 10 is offset to the outside of the crawler belt constituting the lower traveling body 1, and when the work machine 3 is operated, the bucket 10 is displaced in a direction substantially parallel to the crawler belt. In doing so, for example, work such as digging a side ditch can be performed smoothly.

[0005]

By the way, for example, after digging a gutter, in order to finish the gutter, it is necessary to perform finish forming for correcting the shape and the like of the gutter to an appropriate state. . The finish forming operation of the side groove is also performed by using a bucket in a working machine. At this time, it is desirable that the bucket can be moved in an arbitrary direction. For this purpose, for example, it is considered that the arm is connected to the upper boom via a rotation mechanism. However, when such a rotating mechanism is provided, there is a problem that the whole working machine becomes heavy and the structure becomes complicated.

The present invention has been made in view of the above points, and an object of the present invention is to enable the offset function to be exhibited with a simple configuration and to allow the bucket to be moved in any direction. Is to do so.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a boom connected to an upper revolving body so as to be capable of raising and lowering, and an arm connected to a tip of the boom so as to be rotatable in a vertical direction. And a front attachment connected to the distal end of the arm, wherein the boom is composed of a lower boom connected to the upper revolving unit and an upper boom connected to the arm, and between the lower boom and the upper boom. A first offset cylinder connected between the lower boom and the upper boom so as to be rotatable in a direction orthogonal to a rotation direction of the arm, and the upper boom and the arm And a bottom chamber of one of the first and second offset cylinders. A first operating mode in which, when pressure oil is supplied to the storage chamber, the return side is connected to the same chamber of the other cylinder so that the total length of these two cylinders is the same. Operating mode switching means for switching to a second operating mode in which one of the first and second offset cylinders operates alone and the other cylinder is maintained in a non-operating state. The feature is that it has done.

Here, the first and second offset cylinders are constructed of the same arrangement, and one of them is used as a master cylinder and the other is used as a slave cylinder. The cylinder is operated in substantially the same stroke in the direction opposite to the master cylinder so as to operate as a first operation mode for performing the original offset operation, and either the master cylinder or the slave cylinder operates. Even so, the other cylinder can be held in a stopped state, so that it can be operated as a second operation mode in which the arm is rotated so as to swing at least in the horizontal direction with respect to the axis of the lower boom. For this purpose, the operation mode switching means includes a first switching means for selectively supplying pressure oil to the bottom chamber or the rod chamber of the master cylinder, a bottom chamber and a rod chamber of the master cylinder, and a bottom chamber of the slave cylinder. It comprises a second switching means for interrupting the communication with the rod chamber, and an operation mode selecting means for selecting the first operation mode and the second operation mode. When the first operation mode is selected by the operation mode selection means, the first switching means supplies pressure oil to the master cylinder, and the second switching means supplies the hydraulic pressure to the chamber on the return side of the master cylinder and the slave cylinder. The communication between the return side of the master cylinder and the same chamber is performed, and when the second operation mode is selected, the connection between the master cylinder and the slave cylinder is cut off by the second switching means, and the master cylinder or the slave cylinder is disconnected. Pressure oil is supplied to and discharged from one of the slave cylinders. The second operation mode, that is, the cylinder independent operation can be performed by the switching operation of the first switching means. However, the third switching between the hydraulic pump and the independently operated cylinder is performed. A valve can be provided. Of the first and second offset cylinders,
For example, the first offset cylinder may be a master cylinder, and the second offset cylinder may be a slave cylinder. Further, the independently operated cylinder may be either the first offset cylinder or the second offset cylinder.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show the working machine. 20 shows the configuration of the second embodiment. The work machine 20 includes a boom 21 including a lower boom 21a and an upper boom 21b, an arm 22, and a bucket 23. The lower boom 21a is connected to the upper revolving body so as to be capable of raising and lowering, and the upper boom 21b is connected to the lower boom 2
1a, a cylinder stay 24 is connected to the distal end of the upper boom 21b so as to be able to rotate in the horizontal direction, and a base end of the arm 22 is connected to the cylinder stay 24. On the other hand, they are connected so as to be rotatable up and down. Further, a bucket 23 is connected to a tip of the arm 22 via a link mechanism 25. A boom cylinder 26 is provided between the upper swing body and the lower boom 21a, an arm cylinder 27 is provided between the cylinder stay 24 and the arm 22, and further, between the arm 22 and the link mechanism 25. Is provided with a bucket cylinder 28. For the above configuration,
There is no particular difference from the above-described configuration of the related art.

The offset mechanism in the working machine 20 includes a lower boom 21a and an upper boom 2
1b, a first offset cylinder 29 provided between
It comprises a second offset cylinder 30 provided between the upper boom 21b and the cylinder stay 24. The arrangement of the first and second offset cylinders 29 and 30 is the same. That is, both cylinders 29, 30
Have the same structure and the same dimensions. Of these, the first offset cylinder 29 constitutes a master cylinder, and the second offset cylinder 30 constitutes a slave cylinder.

Here, when the two cylinders operate in conjunction with each other, the master cylinder and the slave cylinder are supplied with pressure oil from a hydraulic pump, and the directly operated cylinder is the master cylinder. It can be operated by introducing return oil from the master cylinder. In addition, the operation directions of the master cylinder and the slave cylinder are set to be opposite. For example, when the master cylinder is extended, its rod chamber is on the low pressure side, and hydraulic oil inside flows out, but return oil flowing out of the rod chamber of this master cylinder is introduced into the rod chamber side of the slave cylinder. The bottom chamber of the slave cylinder is connected to the tank. as a result,
When the master cylinder extends a predetermined length, the slave cylinder shrinks by the same length, so that the total length of the master cylinder and the slave cylinder does not change. When the master cylinder shrinks, the bottom chamber of the master cylinder communicates with the bottom chamber of the slave cylinder, and the slave cylinder extends by the reduced length of the master cylinder.

With the above configuration, when the first offset cylinder 29 forming the master cylinder and the second offset cylinder 30 forming the slave cylinder are operated in conjunction with each other, the first offset cylinder 29 The upper boom 2
1b is inclined at a predetermined angle with respect to the lower boom 21a in the left or right direction about the shaft support 31. At the same time, since the second offset cylinder 30 contracts or expands by the same length, the cylinder stay 24 is opposite to the upper boom 21b with respect to the tilting direction of the upper boom 21b about the shaft support 32 therebetween. Incline by about the same angle in the direction. Cylinder stay 2
4 has an arm 22 and the arm 22 has a bucket 2
3 are connected to each other so as not to be able to rotate in the horizontal direction, so that the same offset operation as in the above-described prior art is performed. This is the operation in the first operation mode.

On the other hand, either the first offset cylinder 29 constituting the master cylinder or the second offset cylinder 30 constituting the slave cylinder can be operated independently, and this is the second offset cylinder 29.
In the second operation mode, the axes of the cylinder stay 24, the arm 22, and the bucket 23 are inclined horizontally with respect to at least the axis of the lower boom 21a or the entire boom 21. In addition, the second offset cylinder 30 can be operated independently after the first offset cylinder 29 is interlocked with the second offset cylinder 30 halfway through the stroke. Therefore, when the work machine 20 is operated in these first and second operation modes (including the case where the first and second operation modes are combined), the bucket 23 is moved as shown by a virtual line in FIG. It can be controlled to face any direction.

With the above-described configuration, the work machine 20 is first operated in the first operation mode to dig a ditch, and then the bucket 23 is operated in the second operation mode.
Is changed so as to face the desired direction,
, The operations such as correcting and forming the excavated gutter can be performed smoothly and accurately.

The first and second offset cylinders 2
9 and 30, the first offset cylinder 29 is a master cylinder and the second offset cylinder 30 is a slave cylinder. Conversely, the second offset cylinder 30 is a master cylinder and the first offset cylinder 29 is a master cylinder. The cylinder 29 may be a slave cylinder. Also,
The cylinder that operates alone in the second operation mode may be either the first offset cylinder 29 or the second offset cylinder 30.
It is also possible to configure each of the 30's to operate independently. In short, when one of the two offset cylinders functions as a master cylinder, the other may be configured to function as a slave cylinder that operates by the same stroke in the opposite direction to the master cylinder. .

Next, FIG. 3 shows a configuration of a hydraulic circuit for operating the first and second offset cylinders 29 and 30 as described above. Here, in the following description, 2
Of the offset cylinders, 40 is a master cylinder and 41 is a slave cylinder.

Reference numeral 42 denotes a hydraulic pump for supplying pressure oil to the master cylinder 40; 43, an operation lever for offset; 44a, 44b pilot valves; 45, a pilot pump; and 46, an operation mode selection means. The hydraulic pump 42 is connected to a first switching valve 47. The first switching valve 47 is connected to a high-pressure pipe 4 from the hydraulic pump 42.
8 for switching between a switching position (A) connecting the pipeline 49 to the master cylinder 40 side and a switching position (B) connecting the pipeline 50 to the slave cylinder 41 side. . Line 49 is the first spool valve 51
The first spool valve 51 is connected to a switching position (c) for supplying pressure oil from the hydraulic pump 42 to a pipe line 52 connected to the rod chamber side of the master cylinder 40, and to the bottom chamber side. The switching position (d) for supplying the pressure oil to the connected pipe 53 and the neutral position (e) for shutting off the pipe 49 are switched. The pipe 50 is connected to a second spool valve 54. The second spool valve 54 is also connected to a tank 55. A pipe 56 connected to the rod chamber of the slave cylinder 41 and a pipe 57 connected to the bottom chamber are connected to the second spool valve 54. When the second spool valve 54 switches to the switching position (f), the pressure oil from the hydraulic pump 42 is introduced into the bottom chamber, and the rod chamber is connected to the tank 55. Also,
When the position is switched to the switching position (g), the pressure oil from the hydraulic pump 42 is introduced into the rod chamber, and the bottom chamber is connected to the tank 55. Further, at the neutral position (H), the slave cylinder 41 is not in communication with the hydraulic pump 42 or the tank 55.

The pilot pipes 58, 59 from the pilot valves 44a, 44b are branched, respectively, into first pilot pipes 58a, 59a connected to both pilot chambers of the second spool valve 54, and a first spool valve. The second pilot pipes 58b and 59b are connected to the pilot chambers 51 and the second switching valve 60, respectively. Moreover,
In the middle of the second pilot pipes 58b, 59b, the first
A switching position (i) for connecting both pilot chambers of the spool valve 51 and the second switching valve 60 to the pilot valves 44a and 44b, respectively, and these pilot chambers are connected to the tank 55.
An opening / closing valve 61 that is switched to a switching position (nu) that communicates with is provided.

A pipe 62 connected to the pipe 52 and a pipe 63 connected to the pipe 53 are connected to the second switching valve 60, and a pipe 64 and a pipe 57 connected to the pipe 56 are connected. Is connected to the pipeline 65 connected to the pipe. The second switching valve 60 connects the pipe 63 and the pipe 65 to each other, and
A switching position (L) for shutting off the line 2 and the line 64;
Switching position (ヲ) for connecting the pipe 63 and the pipe 64 and disconnecting the pipe 63 and the pipe 65, the pipe 62, the pipe 64 and the pipe 63
And a cutoff position (W) for cutting off the pipe line 65.

In this hydraulic circuit, the first switching valve 47
And the first spool valve 51, the master cylinder 40
The first switching means is configured to switch between a state in which the pressure oil is supplied to the pump and a state in which the supply is stopped.
The opening and closing valve 61 constitutes second switching means for switching between interlocking the master cylinder 40 and the slave cylinder 41 or disconnecting the interlocking relationship. Further, the second spool valve 54 constitutes a third switching valve for switching the slave cylinder 41 to operate alone. Then, the operation mode selecting means 46 controls the first switching valve 4
The first switching valve 47 and the opening / closing valve 61 are operated in conjunction with each other by the operation mode selecting means 46.

When the operation mode selecting means 46 is at the position A, the first switching valve 47 is at the switching position (a) and the opening / closing valve 61 is at the switching position (i).
The first operation mode is a state in which the and the slave cylinder 41 can be operated in conjunction with each other. When the operation mode selection means 46 is switched to the position B, the first switching valve 47 is switched to the switching position (b) and the on-off valve 61 is switched to the switching position (nu), so that the slave cylinder 41 can be operated independently. The second operation mode is set. However, the master cylinder 40 or the slave cylinder 41 actually operates when the pilot valve 44a or 44b is opened and the pilot pressure from the pilot pump 45 is supplied to one of the pilot pipes 58 and 59, that is, the operation lever 43 is operated.

When the operation mode selecting means 46 is in the position A
, The first switching valve 47 is in the switching position (A),
The first operation mode in which the on-off valve 61 is in the switching position (i) is selected. In this state, when the operation lever 43 is tilted in the direction of arrow L, pilot pressure acts on the pilot pipe 58 side. This pilot pressure is
Are supplied to the pilot pipes 58a and 58b. As a result, the first spool valve 51 switches to the switching position (C), the second spool valve 54 switches to the switching position (F), and the second switching valve 60 switches to the switching position (L). As a result, the hydraulic pump 42 communicates with the rod chamber of the master cylinder 40 via the pipes 49 and 52, and
Is supplied to the rod chamber. On the other hand, the bottom chamber of the master cylinder 40 communicates with the bottom chamber of the slave cylinder 41 via the pipe 63 and the pipe 65, and
1 is connected to a tank 55 via a conduit 58. As a result, the master cylinder 40 is reduced, and at the same time, the master cylinder 40
The oil spilled from the bottom chamber is guided to the bottom chamber of the slave cylinder 41 as high-pressure oil, and the oil returns to the tank 55 from the rod chamber and recirculates. It will extend by the same stroke.

Therefore, as a result of the first offset cylinder 29 functioning as the master cylinder 40 shrinking, FIG.
In, the upper boom 21b rotates leftward about the shaft support 31. In addition, at this time, the second offset cylinder 30, which functions as the slave cylinder 41, extends, and the extension stroke is substantially the same as that of the first offset cylinder 29. Therefore, the cylinder stays around the shaft support 32 of the upper boom 2b. 24 (and the arm 22 and the bucket 23) rotates rightward, opposite to the upper boom 21b. As a result, the axes of the cylinder stay 24, the arm 22, and the bucket 23 move substantially parallel to the left with the axis of the lower boom 21a, so that a so-called offset operation is performed.

When the operation lever 43 is tilted in the direction of arrow R, the first and second pilot pipes 59a, 59b
Side is supplied with pilot pressure. Therefore, contrary to the above, the master cylinder 40 extends and the slave cylinder 4
1 is reduced by a stroke substantially matching the stroke in which the master cylinder 40 is extended. As a result, the upper boom 21b rotates rightward about the shaft support 31 and the cylinder stay 24 is moved to the upper boom 21b.
And to the left about the shaft support 32 between them. As a result, the axes of the cylinder stay 24, the arm 22, and the bucket 23 are offset rightward from the axis of the lower boom 21a.

Next, when the position B is selected by the operation mode selecting means 46, the second operation mode in which the first switching valve 47 is in the switching position (b) and the on-off valve 61 is in the switching position (nu) is set. Become. Thereby, the first pilot pipe 5
The pilot pressure acts only on the sides 8a and 59a, and no pilot pressure acts on the second pilot pipes 58b and 59b. Therefore, the first spool valve 51 is held at the neutral position (e), the second switching valve 60 is at the shut-off position, the master cylinder 40 is inactive, and the master cylinder 40 and the slave cylinder 41 are Will not be linked. When the first switching valve 47 is in the switching position (B), the hydraulic pump 42 is connected to the line 50.
Connected to the side.

As a result, when the operating lever 43 is tilted in the direction of the arrow L, the pilot valve 44a is opened and the first
Since the pilot pressure acts on the side of the pilot pipe 58a, the second spool valve 54 is switched to the switching position (f), so that the bottom chamber of the slave cylinder 41 is connected to the hydraulic pump 42, The rod chamber is connected to the tank 55, and the slave cylinder 41 extends. Further, when the operation lever 43 is tilted in the direction of arrow R, the pilot bubble 44b is opened and the pilot pressure acts on the first pilot pipe 59a side, so that the second spool valve 54 is moved to the switching position (g). The switching is performed, and the slave cylinder 41 is reduced.

Therefore, in the second operation mode, the first offset cylinder 2 serving as the master cylinder 40
9, the lower boom 21a and the upper boom 21b are integrally held, so that the lower boom 21a and the upper boom 21b perform the same function as the mono boom, and since the slave cylinder 41 expands and contracts independently, the boom The arm 22 can be rotated in the horizontal direction with respect to the arm 21. Furthermore, the cylinder may be operated in the first operation mode until the middle of the stroke, and then the mode may be switched to the second operation mode. As a result, the bucket 23 can be arranged at an arbitrary position, and the direction of movement of the bucket 23 during excavation or the like can be freely controlled. This makes it possible to perform operations such as excavation and forming grooves after excavation extremely smoothly, easily, and accurately.

[0028]

Since the present invention is constructed as described above, the offset function can be exhibited with a simple structure, and various effects such as the bucket can be moved in any direction can be achieved.

[Brief description of the drawings]

FIG. 1 is a front view of a working machine showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a hydraulic circuit diagram for operating an offset mechanism of a work machine.

FIG. 4 is a front view of a hydraulic shovel equipped with a conventional working machine.

FIG. 5 is a plan view of a conventional working machine.

[Explanation of symbols]

Reference Signs List 20 work machine 21 boom 21a lower boom 21b upper boom 22 arm 23 bucket 24 cylinder stay 29 first offset cylinder 30 second offset cylinder 31, 32
Shaft support 40 Master cylinder 41 Slave cylinder 42 Hydraulic pump 46 Operation mode selecting means 47 First switching valve 51 First spool valve 54 Second spool valve 60 Second switching valve 61 Open / close valve

Claims (4)

[Claims] The boom includes a boom connected to the upper swing body so as to be capable of raising and lowering, an arm connected to a tip of the boom so as to be vertically rotatable, and a front attachment connected to a tip of the arm. Is composed of a lower boom connected to the upper revolving unit and an upper boom connected to the arm, and between the lower boom and the upper boom is rotatable in a direction orthogonal to the rotation direction of the arm. A first offset cylinder connected between the lower boom and the upper boom; a second offset cylinder connected between the upper boom and the arm; When pressurized oil is supplied to the bottom chamber or the rod chamber of one of the cylinders in the second offset cylinder, the return side is set to the other cylinder. A first operating mode in which the two cylinders are operated in such a manner that the total length of the two cylinders is the same, and one of the first and second offset cylinders is operated independently. And an operation mode switching means for switching to a second operation mode in which the other cylinder is maintained in a non-operating state. 2. The method according to claim 1, wherein the first and second offset cylinders have the same arrangement, one of them being a master cylinder and the other being a slave cylinder.
The operation mode switching means includes first switching means for selectively supplying and stopping supply of pressure oil to a bottom chamber or a rod chamber of the master cylinder, and a bottom chamber or a rod chamber of the master cylinder and the slave cylinder. Switching means for interrupting communication between the first operation mode and the second operation mode.
And an operation mode selecting means for selecting the operation mode of the above. When the first operation mode is selected by the operation mode selecting means, the first switching means supplies pressure oil to the master cylinder. The second switching means communicates the return chamber of the master cylinder with the same chamber of the slave cylinder as the return cylinder of the master cylinder, and when the second operation mode is selected, The second switching means disconnects the connection between the master cylinder and the slave cylinder, and supplies and discharges pressure oil to or from one of the master cylinder and the slave cylinder. 2. The offset device for a working machine according to claim 1. 3. The offset device for a working machine according to claim 2, wherein a third switching valve is provided between the hydraulic pump and the independently operated cylinder. 4. The master cylinder is the first offset cylinder, and the slave cylinder is the second offset cylinder.
3. An offset cylinder according to claim 2, wherein
The offset device of the working machine as described in the above.